The present invention relates to a magnetic head for a magneto-optical disc drive, and more particularly to an up/down mechanism for moving the magnetic head toward and away from a magneto-optical disc.
Conventionally, a magnetic head is employed in a data recording/reproducing device utilizing a magneto-optical disc or a magnetic disk, for applying a magnetic field to the magneto-optical disc or the magnetic disk. In particular, among various recording/reproducing devices, one employing a floating type magnetic head has been known. The floating type head is constructed such that the head is urged toward the recording medium such as the magneto-optical disc, while, due to the air flow generated by revolution of the recording medium, the head stays at a position a predetermined distance spaced from the data recording surface of the disc.
In such a data recording/reproducing device, there is provided a magnetic head up/down mechanism which moves the magnetic head to locate at either an operative position at which the magnetic head is close to the disc, or at a retracted position at which the magnetic head is spaced from the disc by a relatively large amount.
When the recording medium or a cartridge accommodating the recording medium is loaded or unloaded, the magnetic head is located at the retracted position at which the magnetic head does not interfere the loading/unloading movement of the recording medium or the cartridge. When the recording medium or the cartridge has been loaded, the recording medium is revolved with the magnetic head located at the retracted position, and then, the magnetic head is moved to the operative position. As described above, due to the air flow generated by the revolution of the recording medium, the magnetic head, which is urged toward the recording medium, is located at a position spaced from the data recoding surface of the recording medium by a predetermined amount.
The conventional magnetic head up/down mechanism generally has a lot of parts and a complicated structure, which tends to increase the manufacturing cost.
In particular, in the magneto-optical disc drive, an optical head and a driving unit thereof should also be provided besides the magnetic head and the up/down mechanism, a magnetic head up/down mechanism having a relatively simple structure has been desired.
It is therefore an object of the present invention to provide an improved magnetic head up/down mechanism having a relatively small number of parts and a simple structure, requiring only a relatively small amount of room to install, and can be inexpensive.
For the above object, according to the present invention, there is provided a magnetic head up/down mechanism for an magneto-optical disc drive, the magneto-optical disc drive recording/reproducing data on a magneto-optical disc, the mechanism being mounted on a carriage movable along a radial direction of the optical disc. Further, the mechanism is provided with a magnetic head, a magnetic head supporting member mounting the magnetic head, an elongated plate spring member, the magnetic head supporting member being secured at an end portion in a longitudinal direction of the plate spring member, and a moving system that moves the plate spring member together with the magnetic head supporting member mounting the magnetic head to move between an operative position and a retracted position, the moving system being located on one side with respect to data recording surface of the magneto-optical disc. It should be noted that the magnetic head is capable of applying magnetic field to the magneto-optical disc when the magnetic head is located at the operative position, and the magnetic head is retracted from the operative position and spaced from the magneto-optical disc when the magnetic head is located at the retracted position.
With this structure, the magnetic head up/down mechanism is constituted with a small number of elements, and can be made compact.
According to another aspect of the invention, there is provided a magnetic head up/down mechanism for a magneto-optical disc drive, the magneto-optical disc drive recording/reproducing data on a magneto-optical disc, the mechanism being mounted on a carriage movable along a radial direction of the optical disc, in which provided are a magnetic head, a magnetic head supporting member mounting the magnetic head, an elongated plate spring member, the magnetic head supporting member being secured at an end portion in a longitudinal direction of the plate spring member, and a moving system that moves the plate spring member together with the magnetic head supporting member mounting the magnetic head to move between an operative position and a retracted position. Further, the magnetic head is capable of applying a magnetic field to the magneto-optical disc when the magnetic head is located at the operative position. The magnetic head can be retracted from the operative position and spaced from the magneto-optical disc when the magnetic head is located at the retracted position. Additionally, the operative position and the retracted position are located between an objective lens of the disc drive and the data recording surface of the magneto-optical disc.
Also with this structure, the magnetic head up/down mechanism can be constituted compact in size with a less number of elements.
Optionally, in either of the above structures, the moving system may include a body member rockable about an axis that is parallel with the data recording surface of the magneto-optical disc, the other end of the elongated plate spring being secured to the body member, and a driving system that is actuated to drive the body member to rotate so that the magnetic head is moved between the operative position and the retracted position.
Further, the moving system may include a holding system that holds the body member when the driving system is deactuated. The driving system can be deactuated when the magnetic head has been moved to one of the operative position and the retracted position from the other one of the operative position and the retracted position.
In a specific example, the moving system may include a permanent magnet provided on the body member. The N pole and S pole of the permanent magnet should be arranged in a direction in which the body member rocks. Further, a magnetic field generator is provided on the carriage, the magnetic field generator facing the permanent magnet. With this structure, the body member may be biased to rotate such that the magnetic head is moved toward one of the operative position and the retracted position depending on the magnetic field generated by the magnetic field generator.
Alternatively, the moving system may be constituted to such that a permanent magnet is provided on the carriage, and a magnetic field generator is provided on the body member. Also with this structure, the body member can be biased to rotate such that the magnetic head is moved toward one of the operative position and the retracted position depending on the magnetic field generated by the magnetic field generator.
Optionally, the magnetic field generator may include a first magnetic member and a second magnetic member. The first and second magnetic members are arranged along a direction in which the body member rocks, and the first magnetic member may be closer to the S pole of the permanent magnet when the magnetic head is located at one of the operative position and the retracted position than a case in which the magnetic head is located at the other one of the retracted position and the operative position, while the second magnetic member may be closer to the N pole of the permanent magnet when the magnetic head is located at the other of operative position and the retracted position than a case in which the magnetic head is located at the one of the operative position and the retracted position.
Further optionally, when the magnetic head is located at the one of the operative position and the retracted position, the body member may stay at a current position due to attractive force between the S pole of the permanent magnet and the first magnetic member, and when the magnetic head is located at the other of the operative position and the retracted position, the body member stays at a current position due to attractive force between the N pole of the permanent magnet and the second magnetic member.
Further optionally, that the carriage mounting the magnetic head up/down mechanism may also mount an objective lens.